@SilverTrees my advice is a tip my 16yo gave to my 13yo in my presence, is that in medias like SnapChat, Instagram and Twitter, use the 'mute' buttons. It's a saving face mechanism without needing to be swept under by the barrage of information.
Kids these days use a different meaning for trolling, it's about silly, over the top gestures-memes, videos, photos, but harrassing behavior is exactly what it means. That's the stuff the report buttons are for.

Trolling in discussion type forums can mean, stirring the pot, creating controversy. I think it's more prevalent in other communities.
Then there's simple rudeness, cold shoulder or attempts at being disdainful-which is more likely elsewhere, I think PC is created with more safety measures than most anywhere else.